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California Regional Water Quality Control Board <br /> Central Valley Region <br /> ion '< <br /> f <br /> Steven T.Butler,Chair <br /> Winston H. Hickox Gray Davis <br /> Secretaryjor Sacramento Main Office Governor <br /> Environmental Internet Address: http://www.swrcb.ca.gov/—rwgcb5 <br /> Protection 3443 Routier Road,Suite A,Sacramento,California 95827-3003 <br /> Phone(916)255-3000•FAX(916)255-3015 <br /> TO: Bob Matteoli FROM: Camilla Williams <br /> Senior WRC Engineer Associate Engineering Geologist <br /> DATE: 29 July 1999 SIGNATURE: <br /> SUBJECT: SITE MONITORING WORKPL.4N, SEBASTIANI VINEY-4P-0S, S.4N J0.4QUIN <br /> COUNTY <br /> I have reviewed the Site Monitoring Workplan (Workplan) for Sebastiani Vineyards, submitted on 6 July <br /> 1999 by NOA Environmental. The Workplan is acceptable, provided the following issues are addressed. <br /> Responses to the following comments should be provided no later than 30 day after receipt to assure <br /> appropriate modifications are made to the Workplan prior to commencement of the field program. <br /> My comments are provided below based on the topics as presented in theWorkplan. The page number <br /> for each identified section is also provided. <br /> Site Monitoring Methodologies and Specifications (Page 13) <br /> The Workplan indicates that three groundwater monitoring wells will be installed to sample the first <br /> saturated water bearing zone. Flow direction at both the eastern and western facilities is reported to be <br /> westerly/northwesterly. The upgradient well is proposed for installation in the northwestern corner of <br /> the eastern facility. Two downgradient monitoring wells are proposed for installation near the midpoints <br /> of the western boundaries of the western most treatment pond and storage lake. Assuming this flow <br /> direction is correct, then the proposed well at the eastern facility is not upgradient of the treatment ponds <br /> and constructed wetlands. A more appropriate location of the upgradient well (assuming adequate <br /> access) may be in the southern portion of the eastern facility. In addition, if there is a northwesterly <br /> component to the flow direction, then it may be appropriate to relocate the downgradient wells slightly <br /> northward. <br /> Other than indicating that the monitoring wells will be installed in the uppermost water-bearing zone, the <br /> Workplan does not specify the target depth or screen interval. The Workplan provided the American <br /> Society for Testing and Materials (ASTM) specifications for design and installation of groundwater <br /> monitoring wells (ASTM D 5092-90); however, this information is general in nature and is not site- <br /> specific. Because several monitoring wells were installed at the eastern facility for an underground <br /> storage tank investigation, it is not unreasonable to assume that target well depths, screen intervals, slot <br /> size, and filter pack could have been proposed in this Workplan. A construction diagram with the site- <br /> specific proposals should have been submitted in addition to or in lieu of that contained in the ASTM <br /> method. <br /> c:\ckwf i les\wineries\winememos\winemem001 <br /> California Environmental Protection Agency <br /> 0a Recycled Paper <br />